A device that functions as an active suspension interposed between a vehicle body and an axle of a vehicle, for example, is available as a suspension device. More specifically, this suspension device is configured to include: a suspension main body having a cylinder, a piston that is inserted into the cylinder to be free to move and defines a pressure chamber within the cylinder, and a rod coupled to the piston; a hydraulic pump; an oil passage that connects the pressure chamber in the suspension main body to the hydraulic pump; a solenoid open/close valve provided midway in the oil passage in order to open and close the oil passage; a solenoid pressure control valve that controls the pressure in the pressure chamber; and a solenoid failsafe valve for performing a fail operation when a system failure occurs (see JPH9-240241A, for example).